1. Field of the Invention
This invention relates to an electrode and a lead wire therefor used for taking a cardiogram or an electroencephalogram, and more particularly to an X-ray transmissive electrode and a lead wire therefor suitably used for taking an X-ray photograph while the electrode remains attached to the body of a patient, and to a method of manufacturing the same.
2. Description of the Prior Art
Heretofore, metallic electrodes and shielded wire were used for the extraction of biosignals for preparation of a cardiogram or the like. The metallic electrode was brought into contact with the patient's body as by use of an adhesive, and one end of the electrode was connected to the electrically conductive core of the shielded wire, with the shield portion provided around the metallic electrode being connected to the shielded portion of the shielded wire to prevent electrostatic or electromagnetic noise from mixing with the biosignals.
Furthermore, when taking an X-ray photograph during measurement, the electrode had to be removed from the patient's body to prevent the image of the electrode from appearing on the photographic film. Such adverse effects may be reduced by having the size of the electrode and the diameter of the shielded wire extending from the electrode as small as possible. However, certain areas desired to be photographed were still masked by the electrode and the shielded wire, thus interfering with accurate X-ray photography and proving a hindrance to diagnosis.
It may be desired from time to time to take an X-ray photograph while visually inspecting the waveshape of the cardiogram or electroencephalogram. In this case, since the electrode and the shielded wire cannot be removed from the patient's body, indistinct portions may appear on the photograph due to obstructions presented by the electrode and the shielded wire. In order to overcome such problems, electrodes penetrable by X-rays have been devised. For instance, the Japanese Patent Application Laid-Open No. 118873/1977 discloses such an X-ray transmissive electrode comprizing an extremely thin gold layer deposited on a Mylar (polyethylene telephthalate) plastic base film. The electrode is connected to a single core copper wire clamped and reinforced by a plastic tape. Japanese Patent Application Laid-Open No. 118989/1977 and 93681/1978 both disclose substantially carbon electrodes for biological use. It is contemplated that X-ray transmissive electrodes for biological use may be obtained by using carbon fibers or very thin carbon layers. However, there has not yet been devised an X-ray transmissive electrode and a shielded wire that may be produced easily and at minimal cost.